Single Step Protocol and Multi-step Warming Protocol for Blastocyst FET

Официальное название

The Live Birth Rate Between Single and Multi-step Warming Protocol Applied in Blastocyst Vitrification: a Randomized Controlled Trial

Обзор

The multi-step thawing protocol with a reduction of non-permeable cryoprotectant concentrations to reduce osmotic shock caused by the rapid influx of water. Recent studies have shown that a simplified warming protocol by only a thawing solution gave a comparable survival rate but increased pregnancy rate, reduced patients' waiting time, and decreased the workload of embryologists.

Подробное описание

Nowadays, vitrification is the gold standard method in freezing human embryos, using different commercial brands of ready-to-use kits. Removing cytotoxic cryoprotectants and rehydration to prevent osmotic shock has been a fundamental principle in cryobiology. This minimized damage during the vitrification/thawing (V/T) process. However, the entire process is time-consuming and labor-intensive in the IVF laboratory. Especially, some laboratories have difficulty ordering the same brand of medium for V/T kits. Because of the long period of cryopreserved embryos, it may be that embryos were vitrified and warmed with different kits with a potentially different kind and concentrations of cryoprotective agents. Recently, the combinations of the two different V/T commercial kits have shown comparable survival, blastulation, and implantation rates in both own and donor oocyte cycles.

Additionally, there remains an opportunity and a necessity to continue improving the warming protocol. The key factors for thawing require a fast warming rate, a gradually decreasing concentration of intracellular cryoprotectant, and embryologist skills to secure the survival rate.

Based on previous work, one option would be shortening the time necessary to rehydrate. A study by Seki and Mazur has shown that embryo survival is almost entirely dependent on the warming rate rather than the extracellular cryoprotectant concentration used. A recent study by Liebermann showed that simplifying warming procedures in one step by using 1M sucrose only is possible with an encouragingly higher ongoing pregnancy rate and comparable clinical outcomes when compared to the same conventional multi-step warming protocol, showing a significantly lower miscarriage rate (4.0% vs. 7.6%). These results lead to a faster, safer, and more cost-effective procedure.

This study aims to investigate the effectiveness and safety of a new combination of V/W solutions-single and multi-step thawing protocol- on live birth rate (LBR), as well as embryo transfer, obstetric, and neonatal outcomes.

Вмешательства

• Процедура Single-step warming protocol by thawing solution only
  Potentially eligible patients' vitrified blastocysts will be thawed by a single-step thawing protocol. For the warming phase, vitrified blastocysts are exposed to the thawing solution of a commercial embryo thawing kit (Irvine Scientific Inc., USA) at 37°C for one minute. Immediately following this, embryos will be rinsed in a 35mm diameter dish of 2ml of pre-equilibrated thawing solution before being placed in culture media in the incubator for at least 2 hours before transfer.
• Процедура Standard warming protocol
  For the MS protocol, thawing kits were equilibrated overnight in a 37°C incubator. Warming procedures utilized the kits (Cryotech RtU, Japan). To remove the cryoprotectants, blastocysts were warmed, and cryoprotectants were diluted in a three-step process. The warming process starts with the exposure of blastocysts to thaw solution (TS) with 1M trehalose for one minute at 37°C. Subsequently, the blastocyst will be transferred to a second well containing a dilution solution (DS) of 0.5M trehalos

Первичные конечные точки

• Live birth rate [Срок оценки: At 22 weeks of gestation]

Вторичные конечные точки (12)

• Survival rate [Срок оценки: At least 2 hours after thawing.]
• Cancellation rate [Срок оценки: Any day during endometrium preparation days before embryo transfer.]
• Positive pregnancy test [Срок оценки: At 2 weeks after embryo placement]
• Implantation rate [Срок оценки: At 3 weeks after embryo placement]
• Clinical pregnancy [Срок оценки: At 5 weeks after embryo placement]
• Ectopic pregnancy [Срок оценки: At 7 weeks of gestation]
• Ongoing pregnancy [Срок оценки: At 10 weeks after embryo placement]
• Miscarriage [Срок оценки: before 22 completed weeks of gestational age]
• Preterm delivery [Срок оценки: At 22, 28, 32 weeks and 37 weeks of gestation]
• Major congenital abnormalities [Срок оценки: At birth]
• Birth weight [Срок оценки: At the time of delivery]
• Low birth weight [Срок оценки: At the time of delivery]

Критерии участия

Критерии включения

• Women aged from 18
• Undergoing no more than 3 previous IVF/ICSI cycles
• Had at least a single good-quality blastocyst frozen.
• Endometrium preparation using artificial cycle
• Agree to single blastocyst transfer
• Not participating in any interventional studies at the same time

Критерии исключения

• Embryos from cycles after in-vitro maturation, pre-implantation genetic testing (PGT)
• Having contraindications for exogenous hormone administration (e.g., breast cancer, thromboembolic disease)
• Having uterine abnormalities (e.g., adenomyosis, intrauterine adhesions, unicornuate/ bicornuate/ arcuate uterus; unremoved hydrosalpinx or endometrial polyp)

Критерии приведены из реестра в оригинале (на английском). Окончательную оценку соответствия проводит исследовательский центр.

Здоровые добровольцы: Нет

Дизайн исследования

Распределение

Рандомизированное

Модель

Параллельные группы

Маскирование

Открытое

Основная цель

Лечение

Центры проведения

Вьетнам · 1 центр

• My Duc Hospital — Ho Chi Minh City

Публикации

• Connolly MP, Hoorens S, Chambers GM; ESHRE Reproduction and Society Task Force. The costs and consequences of assisted reproductive technology: an economic perspective. Hum Reprod Update. 2010 Nov-Dec;16(6):603-13. doi: 10.1093/humupd/dmq013. Epub 2010 Jun 8. PMID 20530804
• Seki S, Mazur P. The dominance of warming rate over cooling rate in the survival of mouse oocytes subjected to a vitrification procedure. Cryobiology. 2009 Aug;59(1):75-82. doi: 10.1016/j.cryobiol.2009.04.012. Epub 2009 May 7. PMID 19427303
• Gallardo M, Saenz J, Risco R. Human oocytes and zygotes are ready for ultra-fast vitrification after 2 minutes of exposure to standard CPA solutions. Sci Rep. 2019 Nov 5;9(1):15986. doi: 10.1038/s41598-019-52014-x. PMID 31690725

Идентификаторы

NCT: NCT07088640 · 07/25/DD-BVMD

Первоисточники (государственные реестры)

• ClinicalTrials.gov (NIH, США)

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